Color photography



Patented res; so, reeo h FATE vooLon rnoroonhrnr Abruhom Bovley, Blnghamton, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing- Aooiicaiulm October'l, 194e,.

I Serial No. 504.595

ll. (Helms.- This inventon relates to the production oi color ment and more particularly to new coupling compounds therefor. v

The new color coupling compounds are described in my copending application Seriel No. d90,632,'flled June 12, wet, or which the present application is a. continuation-import.

groups, one R1 always being the aforesaid ecylphotographic images by color-forming developaceto group. y

R2 may be an allsyl, cycloalkyl, arelkyl, oryl or heterocyclic group, e. g., methyl, ethyl, propyl,

It is known to form color photographic images v by development of an exposed silver halide emulsion with an aromatic "amino developer in the presence of a coupling compound or color former. The color former may be present in the emulsion or in the developing solution and in the develophient process couples with the oxidation prod not of the aromatic amino developer to form a, dye image in the emulsion. The developed emulsion may then be bleached for removal of the silver image leaving the color image in the emulsion.

1 have found that an improvement in producing photographic color pictures by color-forming development may he obtained by employing as the color formers or coupling compounds copeble of forming at dyestuff with the oxidation product of an aromatic amino developer, eralkyl and eryl guanozols (3.5-diemino-1.2. l-triazoles Beilstein (4th ed.) 26', 193, 195) in which at least one and preferably both of the amino groups on the triazole ring are mono-substituted by an ecyleceto group. The coupling compounds have the following general formula:

wherein R represents an aralkyl 0r eryl radical, e. g. benzyl, phenyl, nephthyl, unthrenyl, diphenyl and the like, which further may be substituted by such groups as halogen atoms, e. g. chlorine,

bromine, etc., nitro, amino, sulfo, hydroxyl, care wherein R2 represents on organic radical which is free from color-formins phenolic hydroxyl decyl, stearyl, cyclohexyl, naphthenyl, obletyl, benzyl, phenyl, naphthyl, anthronyl, ollphenyl, pyridyl, qulnolyl, thlazolyl, furyl, etc.-, which groups further may be substituted in the case of the groups R with the exception that in the case of hydroxyl substituents they should not with the aryl group constitute color-forming phenolic hydroityl groups.

It is known in the ort that the development of an exposed silver halide emulsion with e primary aromatic amine in the Presence of a com pound containing on ecyleceto grou leads to theformation of yellow dyestufi images. similarly, the art is cognizant of the feet that the development of an exposed silver halide emulsion with a primary aromatic amine in the presence of a phenol, th hydroxyl grou or groups of which are pure to o reactive coupling center, i. e., e free position or one occupied by e, group which splits ch in the coupling reaction, produces cyan images. If, therefore, there were present in the color formers of thepresent invention such phenolic groups in addition to the ocylsceto groups, dyestuif images would result upon color-forming development which would not possess th iin-g tended color. Consequently, in order for the color formers of the present invention to function in color photography in the manner intended, it is essential that 'they'be free from color-forming phenolic hydroxyl groups.

Where "both of the guan'czol amino groups contain an acyloceto group R1 in accordance with the preferred'embodiment of the invention, this group may be the some or diflerenth In either event, the compounds contain two active methyl- .ene groups which enhance the stability of the color obtained on coupling of the compounds with an aromatic amino developer, e. g. p-omino diethyl aniline, in the presence of an exposed silver halide emulsion.

Among the color-forming compounds embraced 3.5-di (benzoylaceto) -1-phenyl gnanazol SB-GKiuroyhcetM-i-phenyl guanazol or r- -c-mwoomco noocnioo N 3.5-di(nlcotinoylaceto)-1-phenyl guanazol o-Nno 011,0 O-CnHu NHO 0081C 0-CnHu 3.5-di (stearoylaceto) -1-benayl guan azol Iiii-NEH; O C H 0 3.5-di o-naphthoylac eto) -1-naphthyl guanaz ol ON--o-Nnooomoo I t} N Nncoomoo e 3.5-di(pnephthoylaoeto)-1-phenyl guanuol NC-NHCOCH,CO NHC 00113:: O, Q i

NnooomcoO-Nnc ocean I 3.lS-di(p-stearoylaminobenzoylscetol-l-phenyl guannzol ON-o-Nncoorno 0G NHCOCHSC 00H:

I a'eeetylaoeto-o-benroylaceto-l-phenyl guana'zol 3 /CH 3 o NHOOCHaCOCH:

3-scetylaeeto-5-iuroylaoeto-l-benzyl guanazol In general the new coupling compounds are water-insoluble. Their solubility in .water may be increased. however. by the introduction of suitable solubilizing groups, e. sulio or carby so enlarging the molecule of the color formers with one or two mols of a p-lreto acid ester or the formula:

RrCOCHzCOORawherein R and R2 are as defined above and R3 is a simple alkyl group, e. g., methyl or ethyl. A well-known example of the B-keto acid esters is acetoacetic ester. I

The .color formers may be added to the developer orto the emulsion and in the form of solutions or suspensions in solvents such as 1N alcoholic sodium or potassium hydroxide, ace- 1 1 tone, ethyl alcohol, lsopropyl alcohol, etc. Disparsing agents such as isopropyl naphthalene sulionic acid may he used in preparing the suspen sions of the insoluble color formers and for assisting in dispersing these color formers in the emulsion.

The color former and solvent may be'employed in the following ratio:

Color former grams 0.1- Solvent no 2 In the event that the color formers are located .in the emulsion layer, it is necessary that the constitution thereof be such that they will not migrate from one layer to the other, else color distortion would result upon color-forming development. It has been proposed to prevent mlgration 01' color formers from silver halide emulsion layers by rendering such color formers fast to diffusion in gelatin." This result may be accomplished in several ways, for instance, by including in the color formers proper a group which in the sense of the dyestufi art is substantive or that it is incapable of diiiusing from gelatin. Examples of color formers which are rendered fast to diffusion by the first method are disclosed in U. S. P. 2,179,228. Examples of color formers which are rendered fast to diffusion by the second method are,cllsclosed in U. S. Patents 2,178,612, 2,179,244, 2,186,719, 2,186,732, 2,186,849, and 2,186,734. It will be seen from a reference to the latter patents that the color formers thereof have been modified by the inclusion of radicals of resins, of polypeptides, of hydrogenated ring systems, of carbohydrates, of long alkyl chains, and by having the radical of the color formers recur a number of times in the final molecule. It is to he understood that the color formers of the present invention may'include substantive groups or molecular enlarging groups (in addition to those previously mentioned) tor the purpose of rendering the same fast to diii'usion.

Any of the aromatic amino developing agents may be used with the color coupling compounds of the invention. Preferred developing agents are the p-amino dialkyl anilines, e. g., p-aminodimethyl aniline and p-amino-diethyl aniline.-

Preferably they are used in the form of salts aeeegr're such as the hydrochloride. The aromatic amino developing agents are characterized by the presence of a free or primary amino group in the molecule which enables the oxidation product of the developer to couple with the color former to form a dye image in the emulsion adjacent the individual particles of the silver image. The silver image may be removed by bleaching with Farmers reducer to leave the color image in the emulsion.

A developer of the following formula may be used with the color formers of the invention:

p-Amino diethyl aniline HCI ....grams 2.5 Sodium sulfite anhydrous "do"..- 0.5 Sodium carbonate anhydrous do 67.5 Potassium bromide do.. 2.5 Water to liter 1 The exposed silver halide emulsions are de- The color former, 3.5-di(acetylaceto)-1-phenyl 'guanazol NCNHC come cm IllHC oomooom was prepared by dissolving 3 parts of phenyl guanazol in 35 parts of dry xylene as solvent and adding thereto 5.35 parts (2.4 mol equiv.) of acetoacetic ester. After refluxing this mixture for 15 minutes, approximately parts of a mixture of the solvent and the alcohol formed was distilled off. The yellow liquid residue was decanted and allowed to cool. The precipitated product after filtering and recrystallizing from ethanol had a melting point of 195 C.

To 10 cc. of a gelatin silver bromide-iodide emulsion one-tenth part of the above color former dissolved in 2 cc. of 1N alcoholic KOH was added with thorough mixing. After coating the emulsion containing the color former onto a suitable support and drying the same it was given a light exposure and developed in solution B. A dye image of excellent yellow color was formed in the emulsion.

Example II Following the procedure of Example I, the color former 3.5-di (benzoylaceto) -1-phenyl guanazol I NHooomo m0 of melting point 218-220 C. was prepared from reacting equivalents of phenyl guanazol and ethyl benzoyl acetate and incorporated in a gelatin silver halide emulsion layer, After exposing the layer to light it was developed in solution B. A yellow dye image of marked clarity of color and distinguished by the absence of orange coloration was formed in the emulsion.

1 claim:

1. IA processof producing a color photographic image in a silver halide emulsion which comprises exposing the emulsion and developing it with a primary aromatic amino developing agent in the presence of a compound selected fromthe group consisting of the acylacetamino-l,2,4-triazoles of the general formula:

RNCNHR1 c -'31 wherein R is selected from the group consisting of aralkyl and aryl radicals, R1 is selected from the group consisting of H and the acylaceto radical COCH2COR2 wherein R2 is an organic radical, R1 being at least once the aforesaid acylaceto radical, said compounds being free from colorforming phenolic hydroxyl groups.

2.A processof producing a color photographic image in a silver halide emulsion which comprises exposing the emulsion and developing it with a primary aromatic amino developing agent in the presence of a 3.5-di(acylacetamino) -l, ,4-triazole free from color-forming phenolic hydroxyl groups and having in l-pcsition oi the trzlazole ring a member of the group consisting oi aralkyl and aryl radicals.

3. A color forming photographic developer comprising a primary aromatic amino developing agent and a compound selected from the group consisting of the acylacetaminoe1,2,d-triazoles of the general formula:

free from color-forming phenolic hydroxyl groups and having in l-position of the triazole ring a member of the group consisting of aralkyl and aryl radicals.

5. A color-forming photographic developer comprising a primary aromatic amino developing agent and a l-pheny1=3.5-di(acetylacetamino)- 1,2,4-triazole free from color-forming phenolic hydroxyl groups.

6. A color-forming photographic developer comprising a primary aromatic amino developing agent and a 'l-phenyl-3.5-di(benzoylacetamino) 1,2,4-triazole free from color-forming phenolic hydroxyl groups.

7. A silver halide emulsion for color photography containing as a color former a compound selected from the group consisting of the acyl acetamino-l,2A-triazoles of the general formula:

wherein R is selected from the group consisting of arelkyl and aryl radicals. R1 is selected from the group consisting of H and the acylaceto' radical COCHaCORc wherein R; is an organic radical, R1 being at least once the aforesaid acylaceto radical, said compounds being tree from coloriorming phenolic hydroxyl groups.

8. A silver halide emulsion for color photography containing as a color former a 3,5-di(acyl-- acetamlno)-i,2,4-triazole tree from color-torming phenolic hydroxyl groups and containing in l-position of the tr'iazole ring a member of the group consisting of aralkyl and aryl radicals.

assume l 3.5 di(p-stearoylaminobenzoylacetami- 1 p y 10 no) -l,2,4-triazole.

ABRAHAM BAVLEY. 

